Method and apparatus for providing controlled atmosphere in mobile mine refuges

ABSTRACT

A system, device and method for rapid delivery of clean air to occupants of a deployed mine refuge from a surface source after the refuge has been deployed and before the self-contained air has been consumed or before the temperature in the refuge has increased to hazardous levels in which a drilling rig is used to a borehole in close proximity to the mine refuge&#39;s underground location and a supply duct is lowered through the borehole to the underground mine near the refuge; upon hearing an alarm sounded by the system, a refuge occupant would exit the refuge, using existing personal breathing protection, to retrieve the duct and connect it to the mine refuge.

BACKGROUND

1. Field of the Invention

This invention relates broadly to providing an atmosphere such that it supports life in spaces that, absent such action, constitute respiratory and/or thermal hazards to person occupying mobile refuges in underground mines. More particularly, this invention relates to methods and apparatus for extending life supporting conditions in mine refuges that have been occupied after an accident.

2. Description of the Related Art

Mine refuges, also known as mine shelters, safe havens, mine chambers and refuge alternatives, are mobile emergency structures designed to isolate occupants from hazardous environments that result from an accident which contaminates the air in the mine such that it threatens survival. As mine refuges are relocated within the mines, their position is noted on mine survey maps to aid in rescue. Current art includes provision for creating and maintaining safe atmosphere inside the mine refuge using self-contained compressed oxygen or chemical production of oxygen, along with a means of removing carbon dioxide from occupants' respiration within the sealed environment, typically for a period of 96 hours. Multiple emergency situations have resulted in durations that would exceed these typical values. Excess heat generated by the miners through normal metabolism is dissipated through the surface of the mine refuge into the surrounding air and rock or through limited duration mechanical or chemical heat absorption techniques. Research by the National Institutes for Occupational Safety and Health indicates that in some mines the upper threshold for human survival may be exceed in less than the typical 96 hours provided.

SUMMARY OF THE INVENTION

The currently available methods for providing safe atmosphere in mine refuges are limited to those life supporting systems provided prior to the occupancy in an emergency, generally less than 96 hours. In addition, while provisions are routinely made to identify the location at which mine refuges are located, and often for access to emergency borehole drilling equipment to reach the location, no means of connecting a deployed refuge to reliable external breathing air is known.

The invention taught herein provides for rapid delivery of clean air to occupants of a deployed mine refuge from a surface source after the refuge has been deployed and before the self-contained air has been consumed or before the temperature in the refuge has increased to hazardous levels.

According to the preferred embodiment, a drilling rig would place a borehole in close proximity to the mine refuge's underground location. A supply duct can be lowered through the borehole to the underground mine near the refuge. Upon hearing an alarm sounded by the system, a refuge occupant would exit the refuge, using existing personal breathing protection, to retrieve the duct and connect it to the mine refuge. The tube allows for the supply of clean air and could be equipped with communication capacity to provide or supplement the exchange of critical information between those taking refuge and those attempting rescue.

Those skilled in the art are provided the option to select a source of supplied air capable of modifying the sensible and latent heat content of air flowing to the refuge such that a differential in vapor pressure at the refuge inhabitants' dermal interface is maintained to promote an evaporation rate that ensures that their body core temperatures can be maintained by their thermoregulatory processes.

One embodiment of the invention includes the means for manufacture of a tube with an integrated communication cable.

Another embodiment of the invention includes the means for lowering an air tube duct through a drilled hole such that it can be recovered by those occupying a refuge.

Yet another embodiment of the invention includes a means of modifying existing mine refuges to accept air provided through a tube duct lowered from the surface.

Therefore, there is provided according to the invention, a method and apparatus for providing a controlled atmosphere in mobile mine refuges including a supply of breathable air from outside the mine, a borehole, a tube duct, and an interconnection apparatus attached to the refuge to connect with the tube duct. The supply of breathable air is in fluid communication with the refuge via a flow path from the supply of breathable air through the borehole, the tube duct, and interconnection then into the refuge.

According to a preferred embodiment of the invention, the tube duct may be placed inside the borehole. According to a more preferred embodiment of the invention, the tube duct is constructed of synthetic rubber fabric or a polychlorinated vinyl fabric. According to another embodiment of the invention, the tube duct may be constructed of a material that allows it to lay flat until supplied with air. According to a further embodiment of the invention, the tube duct may have a nose piece that fits inside the borehole.

According to a further embodiment of the invention, the tube duct may contain a communications cable

According to yet another embodiment of the invention, the nose piece may include a buzzer or horn to alert the inhabitants in the refuge when the nose piece is available to connect to the refuge. According to a preferred embodiment of this aspect, the nose piece may have a cylindrical shaped metal construction with a semi-spherical nose. According to a more preferred embodiment, the buzzer or horn is intrinsically safe.

According to another embodiment of the invention, the refuge structure may be modified with the addition of an interconnection apparatus to accept the tube duct. According to a further embodiment of the invention, the refuge structure may be modified with the addition of an interconnection apparatus to accept the communications cable.

The embodiments of the disclosure described herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Rather, the embodiments selected for description have been chosen to enable one skilled in the art to practice the subject matter of the disclosure. Although the disclosure describes specific configurations supplying breathable air within a mine refuge, it should be understood that the concepts presented herein may be used in other various configurations consistent with this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of existing art in expandable mine refuges.

FIG. 2 is an illustration of existing art in rigid mine refuges.

FIG. 3 is an illustration of arrangement of tube application according to an embodiment of the invention.

FIG. 4 is an illustration of borehole drilling technique according to an embodiment of the invention.

FIG. 5 is an illustration of tube duct being deployed down borehole according to an embodiment of the invention.

FIG. 6 is an illustration of the techniques for manufacturing tube duct according to an embodiment of the invention.

FIG. 7 is an llustration of the tube duct nose piece according to an embodiment of the invention.

FIG. 8 shows a cross-section of the apparatus to accept the tube duct according to an embodiment of the invention.

FIG. 9 shows an isometric of the apparatus to accept the tube duct according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration preferred embodiments of the invention. These embodiments are described in sufficient detail to enable those skilled in the art to make and use them, and it is to be understood that structural, logical or procedural changes may be made.

FIG. 1 refers to one type of current art in mine refuges. In this embodiment the mine refuge, numbered 0110, extends from a ridged container which houses compressed air and oxygen along with a chemical carbon dioxide removal system. The occupants recline in the inflated structure, number 1011, for a period limited by the volumes of supplies provided, typically only 96 hours.

FIG. 2, another embodiment of the mine refuge, numbered 0210, show a rigid refuge which contains compressed oxygen or chemical oxygen production capacity along with a chemical carbon dioxide removal system. The occupants enter and are ensured breathable air for a period limited by the volumes of supplies provided, typically only 96 hours.

As shown in FIG. 3, the invention provides a drilled borehole to the vicinity of the occupied mine refuge can provide a breathable atmosphere for the occupants. Number 0310 illustrates the tube duct of the breathable air system through which surface supplies of air can be provided to the refuge numbered 0311. The tube duct is connected to an existing mine refuge as shown at number 0312 whose details will follow. Surface supplies of air can flow through the tube duct, into the refuge, and out through the pressure activated relief valve, number 0313.

The process of drilling an emergency borehole is illustrated in FIG. 4. Drilling rigs such as used in oil and natural gas production, number 0410, can be deployed to most mining locations with 24 hours. The process of drilling begins when the drill rig is situated over the target mine refuge, 0414, according to the mine survey. The down-the-hole rotary hammer is lowered using appropriate drilling pipe, 0411, which passes high pressure fluids powering the rotary hammer and provides for the removal of drilled material. As the borehole is drilled, a self-sealing casing material is injected that expands and provides a seal between the exposed rock and the borehole leaving a hole of sufficient diameter to allow the tube duct to expand without constriction. When the rotary hammer breaks through the roof of the mine it will be detached and left in the mine for later recovery and the drilling pipes being withdrawn to the surface.

In FIG. 5, a trailer, truck or similar conveyance is shown, with a reel of tube duct, numbered 0510, of sufficient length to allow access to the level of the mine refuge and to allow occupants of the refuge to maneuver said tube duct to the mine refuge interconnection apparatus is positioned near the borehole. In addition, the surface reel is of sufficient length to be extended and connected to the selected surface air supply. A guide hoist, numbered 0511, is positioned directly over the borehole to ensure the tube duct, numbered 0512, is allowed to drop without restrictions.

The tube duct, once retrieved by a mine refuge occupant using their personal breathing device, is connected to the refuge via an interconnect apparatus, numbered 0516. The supply side of the duct, number 0513 is fitted into its connector, and the communication line, number 0515, to its connector. At the beginning of the descent into the borehole, power is supplied to the intrinsically safe buzzer or horn incorporated in the tube duct nose piece described in detail below. Those on the surface will monitor the amperage drawn for the device, noting when it drops to zero, indicating that the nose piece has been disconnected. They will also monitor the withdrawal of the tube from the reel to indicate when the tube has been connected to the mine refuge. At that point they will be able to unroll sufficient tube duct to reach the selected air supply device, cutting the tubing and affixing the appropriate connector. This cannot be done prior, as the distance from the borehole to the mine refuge will not be known, and sufficient slack must be available to allow the person in the mine to connect to the mine refuge.

Now referring to FIG. 6, where the preferred embodiment of the tube duct is constructed of a synthetic rubber fabric or of a polychlorinated vinyl fabric, number 0610. The preferred embodiment is a selection of the material for use in the duct that allows it to lay flat until supplied air, as this enhances the ability of those in the refuge to maneuver the tube duct from the borehole to the mine refuge and connect it. A communications wire, number 0611, is pre inserted into the tube duct to allow a connection to be made from the interior of the mine refuge to the surface.

According to another embodiment of the invention, FIG. 7 illustrates the tube duct nose piece, numbered 0710. In a preferred embodiment, it is of a cylindrical shaped metal construction with a semi-spherical nose, numbered 0711. The sides are connected to each other with an overlapping flange, numbered 0714, that is secured with pin, numbered 0713 and a key, numbered 0715. The tube duct, numbered 0717, is connected to a coupling secured to the inside plate of the semi-spherical nose cone at 0719. The communication cable is connected to an intrinsically safe buzzer or horn located in the nose cone at 0720, the purpose of which is to notify the refuge occupants that the air supply has arrived, guiding them to its location, and providing an indication to those on the surface that it has been retrieved when the alarm is disconnected.

Now referring to FIG. 8, the existing refuge structure, numbered 0810, may be modified with the addition of an interconnection apparatus to accept the tube duct and communication cable numbered 0811, shown here in cross-section. The rectangular box is built to the same structural standards as the mine refuge to which it is to be affixed. It has an inner plate, numbered 0812 to which is attached the connector for the tube duct. Those skilled in the art are able to select from several types of pipe connectors, those shown here are for illustration purposes only. The interconnection apparatus is connected to the existing refuge structure with bolts and a flame resistant gasket. The structure is modified with the opening for the air port at the rear of the interconnection apparatus by cutting appropriate holes.

Further illustration is provided in FIG. 9 where the connection apparatus, numbered 0910, is shown in isometric. In this view the swing-away door, numbered 0911, can be seen with its locking tabs, numbered 0912 and the tamperproof seals, numbered 0913. In addition, the bolts that secure the interconnection apparatus are clearly shown on the flange surrounding the box. 

1. A method and apparatus for providing a controlled atmosphere in mobile mine refuges comprising a supply of breathable air from outside the mine, a borehole, a tube duct, and an interconnection apparatus attached to the refuge to connect with the tube duct, wherein the supply of breathable air is in fluid communication with the refuge via a flow path from the supply of breathable air through the borehole, the tube duct, and interconnection then into the refuge.
 2. The method and apparatus according to claim 1 wherein the tube duct is placed inside the borehole.
 3. The method and apparatus according to claim 1 wherein the tube duct is constructed of synthetic rubber fabric or a polychlorinated vinyl fabric.
 4. The method and apparatus according to claim 1 wherein the tube duct is constructed of a material that allows it to lay flat until supplied with air.
 5. The method and apparatus according to claim 1 wherein the tube duct has a nose piece that fits inside the borehole.
 6. The method and apparatus according to claim 1 wherein the tube duct contains a communications cable.
 7. The method and apparatus according to claim 5 wherein the nose piece contains a buzzer or horn to alert the inhabitants in the refuge when the nose piece is available to connect to the refuge.
 8. The method and apparatus according to claim 5 wherein the nose piece is of a cylindrical shaped metal construction with a semi-spherical nose.
 9. The method and apparatus according to claim 7 wherein the buzzer or horn is intrinsically safe.
 10. The method and apparatus according to claim 1 wherein the refuge structure is modified with the addition of an interconnection apparatus to accept the tube duct.
 11. The method and apparatus according to claim 1 wherein the refuge structure is modified with the addition of an interconnection apparatus to accept the communications cable. 